Process for the production of olefinic rubbery copolymers of modified molecular weight

ABSTRACT

A process for copolymerizing either ethylene with a C3 or above alpha-olefin or ethylene with a C3 or above alpha-olefin and an unconjugated diene in the presence of a Ziegler catalyst for polymerization of olefins, consisting of a transition metal compound component and an organoaluminum compound component, as well as in the copresence of a molecular modifier to produce an olefinic rubbery copolymer, the improvement wherein the copolymerization reaction is carried out in the copresence of an epoxy fatty acid ester as the molecular weight modifier.

United States Patent Shiraishi et al. Aug. 29, 1972 [54] PROCESS FOR THE PRODUCTION OF [56] References Cited OLEFINIC RUBBERY COPOLYMERS UNITED STATES PATENTS OF MODIFIED MOLECULAR WEIGHT 0 3,293,230 12/1966 Coover ..260/93.7 [72] Inventors: Masao ShiraIshI; Kiyoshi Maeda,

both of Yokkalchl Japan Primary Examiner.loseph L. Schofer [73] Assignee: Mitsubishi Petrochemical Co., Ltd., Assistant Examiner Roger Benjamin Tokyo, Japan AttorneySherman and Shalloway [21] Appl 75296 A process for copolymerizing either ethylene with a C or above alpha-olefin or ethylene with a C or above [30] Foreign Application Priority Data alpha-olefin and an unconjugated diene in the presence of a Ziegler catalyst for polymerization of Sept. 27, 1969 Japan ...44/7658l olefins, consisting of a transition metal compound [52] U S Cl 260/80 78 260/88 2 R 252/429 B component and an organoaluminum compound com- [51] m C08f 15/40 ponent, as well as in the copresence of a molecular [58] Fieid 2 80 modifier to produce an olefinic rubbery copolymer,

"""" /42'9 the improvement wherein the copolymerization reaction is carried out in the copresence of an epoxy fatty acid ester as the molecular weight modifier.

10 Claims, No Drawings PROCESS FOR THE PRODUCTION OFOLEFINIC RUBBERY COPOLYMERS OF MODIFIED MOLECULAR WEIGHT This invention relates to an improved process for the production of olefinic rubbery copolymers of modified molecular weight and, in particular, to such .a process wherein not only an excellent molecular weight modifying effect is demonstrated with the use of the molecular weight modifier in a markedly reduced .amount as compared with proposals made heretofore, but also the object of molecular weight modification is achieved with substantially no decline in the yield of the resulting copolymer, as well as without imposing any'restrictions l or the known polymerization operation itself.

More specifically, the invention relates to a process wherein in copolymerizing either ethylene with a C or above alpha-olefin or ethylene with a C or above alpha-olefin and an unconjugated diene in the presence of a Ziegler catalyst for polymerization of olefins, cons'isting of a transition metal compound component and an organoaluminum compound component, as well as in the copresence of a molecular weight modifier to produce an olefinic rubbery copolymer, the copolymerization reaction is carried out in the presence of an epoxy fatty acid ester as the molecular weight modifier.

The production of olefinic rubbery copolymers by copolymerizing either ethylene with a C or above alpha-olefin or ethylene with a C or above alpha-olefin and further an unconjugated diene in the presence of the so-called Ziegler catalyst for polymerization of olefins, consisting of a transition metal compound component and an organoaluminum compound component, and the procedure of causing the copresence in the polymerization system of a molecular weight modifier to serve in the modification of the molecular weight are already known.

As procedures of utilizing a molecular weight modifier in this manner, known are such methods as that wherein the polymerization reaction is carried out in the copresence of hydrogen by introducing same into the polymerization system and that wherein the polymerization reaction is carried out in the copresence of molecular weight modifiers such as amines as tri-n-butylamine and ethyl bromide and diethyl zinc.

However, the utilization of a molecular weight modifier generally poses a problem in that difficulty is experienced in achieving compatibility between the molecular weight modification effect and the amount of the modifier used for achieving the desired effect and/or yield of the polymer.

For example, when hydrogen is used as the molecular weight modifier, of the gas fed, only that portion which dissolves in the solvent and monomer serves directly for achieving the molecular weight modifying efiect. Thus, the efiiciency is poor as compared with the amount of the molecular weight modifier used. Further, since a considerable amount leaves to the outside of the system along with the unreacted gas without becoming dissolved, necessary equipment for recovering and reusing same must be provided. Again, in case of the other modifiers also, if a satisfactory molecular weight modifying effect is to be achieved, the amount used must become comparatively large. On the other hand, the tendency to a decline in the yield of the polymer cannot be avoided, if the amount used becomes comparatively great. Again, in some cases the molecular weight modifier is unsatisfactory in that it is one which is either not readily available or expensive.

Asa result of our research with a view to solving this problem of incompatibility, we found that by carrying out the reaction for the production of the aforesaid olefinic rubbery copolymers in the copresence in the copolymerization system of an epoxy fatty acid ester a compound which has not heretofore been proposed at :all as a molecular weight modifier-not only the molecular weight of the resulting copolymer can be 5 freely modified with the use of a relatively small amount of this modifier, but also the decline in yield was slight.

Accordingly, an object of the present invention is to provide a process for producing olefinic rubbery copolymers of modified molecular weight wherein not only an excellent molecular weight modifying effect is demonstrated with the use of the molecular weight modifier in a markedly reduced amount as compared with the proposals made heretofore, but also the object of molecular weight modification is achieved with substantially no decline in the yield of the resulting copolymer.

Other objects and advantages of the invention will become apparent from the following description.

The C or above alpha-olefins used in the invention process are those alpha-olefins which are known to form olefinic rubbery copolymers either by copolymerizing with ethylene or by copolymerizing with ethylene and an unconjugated diene. These alphaolefins can be used singly or in combinations of a plurality thereof. The C -C alpha-olefins are preferably used. Included are such, for example, as propylene, butene-l, pentene-l, hexene-l, heptene-l, octene-l, isobutylene, S-methyl-pentene-l, nonene-l, decene-l, S-methyll-nonene, 5,5 -dimethyll -octene, 4-methyll-hexene, S-methyl-l-hexene, S-methyl-l-heptene, 4- methyl-l-heptene, 6-methyl-l-heptene and 4,4- dimethyll-pentene.

On the other hand, as the unconjugated diene, all those unconjugated dienes which are used in this type of copolymerization reaction for rendering the copolymer vulcanizable can be used. Those conveniently useable include such, for example, as S-ethylidene-2-norbornene, 1,4-hexadiene, dicyclopentadiene, methyltetrahydroindene and S-methylene 2- norbomene.

The amount in which these comonomers are used will also depend on the class of the C; or above olefins used and can be suitably varied within the range wherein olefinic rubbery copolymers can be formed. Generally speaking, the amount of the C or above alpha-olefins used based on the ethylene in the copolymer formed is on the order of 10-80 mol percent, and preferably on the order of 30-60 mol percent.

Again, the amount of the unconjugated dienes used can also be varied, and the amount of the unconjugated dienes in the copolymer formed is on the order 0.6-4 mol percent hand on the amount of ethylene, and preferably on the order of 0.9-2.5 mol percent.

Further, the catalyst to be used in the copolymerization reaction is the well-known Ziegler catalyst, which is used for polymerizing of olefins. In the invention process the catalyst composed of a transition metal compound component and an organoaluminum compound component is used.

As the transition metal compound component of the catalyst, the compounds of titanium or vanadium, and preferably the compounds of vanadium, can be used. The halides of vanadium and the alkyl vanadates are preferred. As such vanadium compounds, mention can be made of such, for example, as vanadium oxytrichloride, vanadium tetrachloride, vanadium trichloride, triethylvanadate, vanadium acetylacetonate, vanadium tetrabromide, vanadium tribromide, and the like. Also in the case of the organoaluminum compounds the known catalyst com ponents such as trialkylaluminums, dialkylaluminum monohalides, alkylaluminum dihalides and alkylaluminum sesquihalides can be used. As the alkyl in the hereinabove mentioned compounds, preferred are the C,C alkyl groups, while as the halogen, preferred is chloride.

The amount of catalyst to be used, the polymerization temperature as well as other polymerization conditions and operation are well known. Thus, the known conditions and operating procedures can be suitably employed. For examples, the amount of the catalyst used in a molar ratio of aluminum compound/transition metal compound is 310:1 and, as the concentration of the transition metal compound, the use of conditions on the order of 002-01 grams per liter of solvent is most common. As regards the polymerization temperature and pressure, frequently used are, for example, those ranging on the order of 20 to 70C. and 1-25 kglcm In the invention process, as hereinbefore indicated, an epoxy fatty acid ester is used as the molecular weight modifier. As shown by the hereinafter given control experiments, the objects of the present invention cannot be achieved by the use of the ethers having an epoxy group or the like, such, for example, as phenylglycidyl ether, butylglycidyl ether and glycidol.

As the molecular weight modifier to be used in the invention process, preferred are those epoxy fatty acid esters whose number of carbon atoms of the fatty acid portion is l20 and number of carbon atoms of the ester portion is 1-10, particularly preferred being those having 1-18 carbon atoms in the fatty acid portion and 1-10 carbon atoms in the ester portion. These epoxy fatty acid esters can either be used singly or be used as a mixture of a plurality of classes thereof.

As such epoxy fatty acid esters can be mentioned such, for example, as propyl epoxy palmitate, butyl epoxy palmitate, pentyl epoxy palmitate, hexyl epoxy palmitate, propyl epoxy stearate, butyl epoxy stearate, pentyl epoxy stearate, actyl epoxy stearate, epoxidized oleic acid glyceride, glycidyl butylate, glycidyl laurate, glycidyl palmitate, glycidyl stearate, glycidyl succinate and glycidyl adipate.

While the amount of the epoxy fatty acid ester used will vary depending upon the classes of the comonomers and unconjugated dienes, the molar ratio in which they are used to ethylene, the class of catalyst, the amount of catalyst used and the class of the epoxy fatty acid ester, usually an amount ranging on the order of 0005-30 mols per each mol of the organoaluminum compound catalyst component is sufficient. Generally, a fully satisfactory molecular weight modifying effect is achieved with a minimal amount, i.e., a small quantity on the order of 001-1 .0 mol, and preferably 0.02-0.8 mol.

The amount used, as hereinabove indicated, is, for example, on the order of 1/4-fold molar quantity of that required when using the conventional molecular weight modifiers such as amines and corresponds to less than about one-half in terms of weight.

In the invention process, the conventional molecular weight modifier, e.g., hydrogen can be conjointly used, if desired, but this is, of course, not necessary.

According to the invention process, the Mooney viscosity (MLEB; of the resulting copolymer can be optionally adjusted within the range of about 10-120 by suitably adjusting the amount of the epoxy fatty acid ester added within the range hereinbefore indicated.

While no particular restrictions are imposed as to the method of accomplishing the copresence in the reaction system of the molecular weight modifier in carrying out the invention process, it is preferred from the standpoint of the molecular weight modifying effect obtained and the catalytic yield [yield (g) of polymer per unit gram of transition metal compound (gpolymer/g-transition metal compound)] that the copresence is effected by first contacting the ester with the aforesaid organoaluminum catalyst component followed by bringing it into contact with the aforesaid transition metal catalyst component.

For example, the preferred procedure is to either mix and contact the organoaluminum catalyst component and the epoxy fatty acid ester in advance and then introduce the mixture to the reaction zone or introduce the two components to the reaction zone independently of each other either simultaneously or in an optional order, ad thereafter add and contact the transition metal catalyst component.

The so obtained copolymer, excelling particularly in such properties as weatherability, resistance to ozone and heat resistance, finds wide use in the various fields where rubber is used.

For this purpose, in carrying out its usual vulcanization with sulfur, carbon black, retarding oil, vulcanization agent, vulcanizing accelerator, zinc white and stearic acid are added.

The following examples are given for illustrating several modes of practicing the invention.

EXAMPLES I AND II AND COMPARISONS I-IX A 3-liter glass flask equipped with an inlet line for the monomeric gas mixture, a discharge line, a thermometer and a stirrer was purged with nitrogen, after which it was charged with 1,500 ml of dehydrated hexane. Next, a combined solution of a 7.5 weight percent hexane solution of 1.13 grams of ethylaluminum sesquichloride and a 2.0 weight percent hexane solution of the prescribed amount of epoxidized oleic acid glyceride (molecular weight 960 was added, followed by the introduction and dissolving to saturation in hexane with gentle stirring of 3.0 liter per minute of ethylene and 8.0 liter per minute of propylene. While continuing the introduction of the monomers (ethylene and propylene), 3 ml of S-ethylidene norbomene were added, followed by the addition of 0.114 gram of vanadium oxytrichloride to initiate the polymerization reaction. The polymerization temperature was held at for the use of the conventional molecular weight modifiers, are also shown together.

EXAMPLES IV-IX AND COMPARISON XII After carrying out the polymerization reaction for 30 minutes, the feed of ethylene and propylene was 'g .g i 8fi i.? i g if stopped, and the polymerization reaction was terf z which 1 6 y i f tg f minated by adding 600 ml of water to the reaction mixr 0 e y ummum 1O sesqulchloride was added. This was followed by the adture. At the same time, an age reslster (styrenated hem] was added followedb thor g in fth dltlon m the PICSCIIbCd amount of epoxydlzedolele I I d Y t O h S go di 6 acid glyceride (molecular weight 960). Next, 2.8 liters i exme i erem i per minute of ethylene, 8.2 liters per minute of t ct y ene'pmpy ene'et ene nor meme propylene and 0.3 liter per minute of hydrogen were in- F copolymeI f Q the resldual catalyst troduced and dissolved to saturation in hexane. Then. Next hqu'd was allow to after adding 3 ml of S-ethylidene norbomene. 0.114 thereby eparatmg and recoYermg a copolymer gram of vanadium oxytrichloride was added to initiate P Whlch was Subfmtted to usual stfiam the polymerization reaction. The polymerization reaclpp and Vacuum f y oPerat-lons to optam 3 tion was carried out for 30 minutes while holding the SOIld copolymer. The yield of this copolymer, lts Mopolymerization temperature at 20 oney vi i y at P PY Content and lodlne This was followed by treating the reaction mixture as number were me edin Example I to obtain a solid copolymer. The yield, The foregoing experime t as Car Out While Mooney viscosity at 120C, propylene content and using the epoxidized oleic acid glyceride in the varying iodine number were measured, amounts of respectively 0, 0.20 and 0.40 gram. The The foregoing experiment was carried out using the results obtained are shown in Table l,below. epoxidized oleic acid glyceride in the amounts of TABLE 1 Molecular weight modifier Molar ratio To organo- Resulting rubbery copolymeraluminum Amount compound Propylene added catalyst Yield ML 120/ C. content Iodine No. Class (g.) component (g.) 1+8 (wt. percent) number Control 48 105 55 4, 9 Example I Epoxl'dized oleic acid glyceritle 0. 2 0. 045 40 60 56 15. 5 Example II. 0. 4 0. 00 46 57 1G. 0 Control I. 0.2 0. 28 12 52 15 5 Control II 0.4 0.56 5 do 50 16.0 Control III. 0. l 14 25 88 6O 15, 1 Control IV 0. 2 .32 14 5t 15. 7 Control V 0.4 .64 0 .do 16.2 Control VI 1 6 9 70 47 15. 2 (lontrolVII. Gly 0.1 0.3 37 107 57 15. 1 ontrol VIII 3 9 34 107 15. 2 Control IX 1 I (I0 4 1- 2 29 8 5 57 15. 8

lI CC1ICII-. 2 C

H2C CI'I C H2 Q 4 9 1I CCHCH 0H 4 Not measurable.

EXAMPLES III AND COMPARISONS X-XI The experiments were operated exactly as in Examples I and 11, except that the class and amount used of the molecular weight modifier were varied. The results obtained are shown in Table 2, below.

50 respectively 0, 0.15, 0.25 and 0.45 gram. The results thus obtained, the results obtained when the experiment was otherwise carried out in identical manner but the hydrogen was not used, and the results of comparison experiments wherein the molecular weight 1 Not measurable due to irregularity of sample.

By way of comparison, results of comparison experiments, which were carried out in like manner except modifier used in the invention was not used but only hydrogen was fed are shown together in Table 3.

TABLE 3 Amount added of Copolymer cppxidizeg Aniolunt 01 eie aci hy rogen 1 Propylene glyceride used Yield ML 120 C. content (wt. Iodine No. I (g.) (l./min.) (g.) 1+8 percent) number gontrnl]. .l.\. "(fig 6 42 100 6 l4. 0

xarnp F v 0. 3 4 (saturation)} 77 63 4 1x81111151 4 4 --l --l 9 so 3 4 o 1 [0.034] 1 Example \"I 0.25 0. 3

1 H l [0.005651% (saturatiomi 40 66 63 Emmi) If -l 40 72 14 3 1 [0.0565] Example VIII 0. 45 0.3

k i 0.12 1 (saturation)} 37 8 65 Example I v 4 --l 35 q 4 4 I) t [0.101] Example XII 0.3

(sammtmfi 41 so in 14. 1

N ore-The figures in the brackets in the table indicate the molar ratio to organoaluminum compound catalyst component.

EXAMPLES X-XIIl The polymerization reactions were carried out as in Example 1 except that butyl epoxy stearate and octyl epoxy stearate were used as the molecular weight modifier. The yield of the so obtained copolymers, their Mooney viscosity at 120C propylene content and iodine number were measured.

The results obtained are shown in Tables 4 and 5.

Table 4 amt. added Properties of Crude Rubber No. of Butyl 120 C Propylene epoxy ML Content iodine Yield Stearate l 8 (wt Number (g) (a) Control 0 101 62 15.0 42

Ex. X 0.10 82 6] 14.6 40

Ex. Xl 0.40 52 63 14.8 38

Note. The figure in the brackets indicate the molar ratio to the organoaluminum compound catalyst component.

Table 5 amt. added Properties of Crude Rubber No. of Butyl 120 C Propylene epoxy ML Content lodine Yield Stearate l 8 (wt Number (g) (g) Control 0 101 62 15.0 42 Ex. X" 0.10 80 62 15.3 41

[0.057] Ex. X111 0.70 24 61 14.8 36

Note. The figures in the bracket indicate the molar ratio to the organoaluminum compound catalyst component.

copolymerization reaction in the copresence of an epoxy fatty acid ester, wherein the fatty acid portion contains 1-20 carbon atoms and the ester portion contains l10 carbon atoms, as the molecular weight modifier, said epoxy fatty acid ester being present in an amount of from 0.005 to 3.0 mols per mol of said organoaluminum compound component.

2. The process of claim 1 wherein the copresence of said epoxy fatty acid ester is carried out by first contacting said ester with said organoaluminum compound component and thereafter with said vanadium or titanium compound component.

3. The process of claim 1 wherein said epoxy fatty acid ester is selected from the group consisting of propyl epoxy palmitate, butyl epoxy palmitate, pentyl epoxy palmitate, hexyl epoxy palmitate, propyl epoxy stearate, butyl epoxy stearate, pentyl epoxy stearate, octyl epoxy stearate, epoxidized oleic acid glyceride, glycidyl butylate, glycidyl laurate, glycidyl palmitate, glycidyl stearate, diglycidyl succinate and diglycidyl adipate.

4. The process of claim 1 wherein said C or above alpha-olefin is a C -C alpha-olefin.

5. The process according to claim 4 wherein said C or above alpha-olefin is a member selected from the group consisting of propylene, butene-l, pentene-l, hexene-l, heptene-l, octene-l, isobutylene, S-methylpentene-l nonene-l, decene-l, S-methyl-l-nonene, 5,5-dimethyl-1-octene, 4-methyl-1-hexene, S-methyll-hexene, 4-methyl-l-heptene, S-methyl-l-heptene, 6- methyll-heptene and 4,4-dimethyl-l-pentene.

6. The process of claim 1 wherein said unconjugated diene is a member selected from the group consisting of 5-ethylidene-2-norbornene, l ,4-hexadiene, dicyclopentadine, methyl tetrohydroindene and 5- methylene-Z-norbornene.

7. The process of claim 1 wherein an amount of said C or above alpha-olefin in said copolymer is 10-80 mol percent based on the amount of ethylene.

8. The process of claim 1 wherein the amount of said unconjugated diene in said copolymer is 0.6-4 mol percent based on the amount of ethylene.

9. The process of claim 1 wherein said vanadium component is selected from the group consisting of the halides of vanadium and alkyl vanadates.

10. The process of claim 1 wherein said organoaluminum compound component is selected from the group consisting of trialkylaluminums, dialkylaluminum monohalidcs, alkylaluminum dihalides and alkylaluminum sesquihalides. 

2. The process of claim 1 wherein the copresence of said epoxy fatty acid ester is carried out by first contacting said ester with said organoaluminum compound component and thereafter with said vanadium or titanium compound component.
 3. The process of claim 1 wherein said epoxy fatty acid ester is selected from the group consisting of propyl epoxy palmitate, butyl epoxy palmitate, pentyl epoxy palmitate, hexyl epoxy palmitate, propyl epoxy stearate, butyl epoxy stearate, pentyl epoxy stearate, octyl epoxy stearate, epoxidized oleic acid glyceride, glycidyl butylate, glycidyl laurate, glycidyl palmitate, glycidyl stearate, diglycidyl succinate and diglycidyl adipate.
 4. The process of claim 1 wherein said C3 or above alpha-olefin is a C3-C10 alpha-olefin.
 5. The process according to claim 4 wherein said C3 or above alpha-olefin is a member selected from the group consisting of propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, isobutylene, 5-methyl-pentene-1, nonene-1, decene-1, 5-methyl-1-nonene, 5,5-dimethyl-1-octene, 4-methyl-1-hexene, 5-methyl-1-hexene, 4-methyl-1-heptene, 5-methyl-1-heptene, 6-methyl-1-heptene and 4,4-dimethyl-1-pentene.
 6. The process of claim 1 wherein said unconjugated diene is a member selected from the group consisting of 5-ethylidene-2-norbornene, 1,4-hexadiene, dicyclopentadine, methyl tetrohydroindene and 5-methylene-2-norbornene.
 7. The process of claim 1 wherein an amount of said C3 or above alpha-olefin in said copolymer is 10-80 mol percent based on the amount of ethylene.
 8. The process of claim 1 wherein the amount of said unconjugated diene in said copolymer is 0.6-4 mol percent based on the amount of ethylene.
 9. The process of claim 1 wherein said vanadium component is selected from the group consisting of the halides of vanadium and alkyl vanadates.
 10. The process of claim 1 wherein said organoaluminum compound component is selected from the group consisting of trialkylaluminums, dialkylaluminum monohalides, alkylaluminum dihalides and alkylaluminum sesquihalides. 